Zoom Lens and Image Pickup Apparatus Using the Same

A zoom lens comprising in order from an object side to an image side:

• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• a third lens unit having a positive refractive power;
• a fourth lens unit having a negative refractive power;
• and
• a fifth lens unit having a positive refractive power, wherein
• at the time of zooming, each of the first lens unit, the second lens unit, the third lens unit, the fourth lens unit, and the fifth lens unit moves to change distances between the lens units, and
• when there is a camera-shake, an image blur on an image plane is corrected by moving the third lens unit in a direction orthogonal to an optical axis, and
• the following conditional expressions (4) and (5) are satisfied
• 0.02<f3/ft<0.1 (4)
• 1.5<(1−mg3t)×mg4t×mg5t<7.0 (5)
• where,
• f3 denotes a focal length of the third lens unit,
• ft denotes a focal length of the overall zoom lens system at a telephoto end,
• mg3t denotes a lateral magnification of the third lens unit at the telephoto end,
• mg4t denotes a lateral magnification of the fourth lens unit at the telephoto end, and
• mg5t denotes a lateral magnification of the fifth lens unit at the telephoto end.

A zoom lens comprising in order from an object side to an image side:

• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• a third lens unit having a positive refractive power;
• a fourth lens unit having a negative refractive power;
• and
• a fifth lens unit having a positive refractive power, wherein
• at the time of zooming, each of the first lens unit, the second lens unit, the third lens unit, the fourth lens unit, and the fifth lens unit moves to change distances between the lens units, and
• a distance between the first lens unit and the second lens unit at a telephoto end is longer than a distance between the first lens unit and the second lens unit at a wide angle end,
• a distance between the third lens unit and the fourth lens unit at the telephoto end is longer than a distance between the third lens unit and the fourth lens unit at the wide angle end,
• a distance between the fourth lens unit and the fifth lens unit at the telephoto end is longer than a distance between the fourth lens unit and the fifth lens unit at the wide angle end, and
• a distance between the second lens unit and the third lens unit at the telephoto end is shorter than a distance between the second lens unit and the third lens unit at the wide angle end, and
• the first lens unit includes a negative lens which satisfies the following conditional expressions (6) and (8), and a positive lens which satisfies the following conditional expression (7), and
• the first lens unit includes a cemented lens having a negative lens and a positive lens, and at least one positive lens, and
• the following conditional expression (9) is satisfied
• νd1n<50 (6)
• 80<νd1p (7)
• θgF1n<−0.00266νd1n+0.68107 (8)
• −0.15<f1/f1c<0.15 (9)
• where,
• νd1n denotes Abbe's number for a d-line of at least one negative lens in the first lens unit,
• νd1p denotes Abbe's number for the d-line of at least one positive lens in the first lens unit,
• θgF1n denotes a partial dispersion ratio for a g-line and an F-line of at least one negative lens in the first lens unit,
• f1 denotes a focal length of the first lens unit,
• f1c denotes a focal length of the cemented lens in the first lens unit,
• Abbe's number νd1n is indicated by νd1n=(nd1n−1)/(nF1n−nC1n),
• Abbe's number νd1p is indicated by νd1p=(nd1p−1)/(nF1p−nC1p),
• the partial dispersion ratio θgF1n is indicated by θgF1n=(ng1n−nF1n)/(nF1n−nC1n),
• nd1n, ng1n, nF1n, and nC1n are refractive indices for the d-line, the g-line, the F-line, and a C-line respectively, of at least one negative lens in the first lens unit, and
• nd1p, ng1p, nF1p, and nC1p are refractive indices for the d-line, the g-line, the F-line, and the C-line respectively, of at least one positive lens in the first lens unit.